1. Field of Art
The present invention relates to using a magnetic field for depositing one or more layers of materials on a substrate.
2. Description of the Related Art
Various chemical processes are used to deposit material on a substrate. Such chemical processes include chemical vapor deposition (CVD), atomic layer deposition (ALD) and molecular layer deposition (MLD). CVD is the most common method for depositing a layer of material on a substrate. In CVD, reactive gas precursors are mixed and then delivered to a reaction chamber where a layer of material is deposited after the mixed gas comes into contact with the substrate.
ALD is another way of depositing material on a substrate. ALD uses the bonding force of a chemisorbed molecule that is different from the bonding force of a physisorbed molecule. In ALD, source precursor is absorbed into the surface of a substrate and then purged with an inert gas. As a result, physisorbed molecules of the source precursor (bonded by the Van der Waals force) are desorbed from the substrate. However, chemisorbed molecules of the source precursor are covalently bonded, and hence, these molecules are strongly adsorbed in the substrate and not desorbed from the substrate. The chemisorbed molecules of the source precursor (adsorbed on the substrate) react with and/or are replaced by molecules of reactant precursor. Then, the excessive precursor or physisorbed molecules are removed by injecting the purge gas and/or pumping the chamber, obtaining a final atomic layer.
MLD is a thin film deposition method similar to ALD but in MLD, molecules are deposited onto the substrate as a unit to form polymeric films on a substrate. In MLD, a molecular fragment is deposited during each reaction cycle. The precursors for MLD have typically been homobifunctional reactants. MLD method is used generally for growing organic polymers such as polyamides on the substrate. The precursors for MLD and ALD may also be used to grow hybrid organic-inorganic polymers such as Alucone (i.e., aluminum alkoxide polymer having carbon-containing backbones obtained by reacting trimethylaluminum (TMA: Al(CH3)3) and ethylene glycol) or Zircone (hybrid organic-inorganic systems based on the reaction between zirconium precursor (such as zirconium t-butoxide Zr[OC(CH3)3)]4, or tetrakis(dimethylamido)zieconium Zr[N(CH3)2]4) with diol (such as ethylene glycol)).
In such deposition processes, molecules are absorbed on the surface of the substrate, react with material on the surface or replace material on the surface. Depending on the substrate and/or the type of precursor, however, the precursor molecules are not easily absorbed on the surface of the substrate. Alternatively, the precursor molecules may not easily react with or replace material on the surface of the substrate. In such cases, the injection time of the precursor is increased or the process of injecting the precursor is repeated for a number of times to ensure that a sufficient amount of precursor molecules are absorbed in the surface of the substrate. The increased time or repetition of process results in lower efficiency and increased time for depositing materials on the substrate.